(Rio de Janeiro) - Police officers in Rio de Janeiro and São Paulo routinely resort to lethal force, often committing extrajudicial executions and exacerbating violence in both states, Human Rights Watch said in a report released today.

Rio and São Paulo police together kill more than 1,000 people every year in such alleged confrontations. While some of these "resistance" killings by police are legitimate acts of self-defense, many others are extrajudicial executions, the report found.

"Extrajudicial killing of criminal suspects is not the answer to violent crime," said José Miguel Vivanco, Americas director at Human Rights Watch. "The residents of Rio and São Paulo need more effective policing, not more violence from the police."

Unlawful police killings undercut legitimate efforts in both states to curb criminal violence, much of which is carried out by heavily armed gangs. In Rio, these gangs are largely responsible for one of the highest homicide rates in the hemisphere. In São Paulo, despite a drop in homicides over the past decade, gang violence also poses a major threat.

Human Rights Watch obtained credible evidence in 51 "resistance" cases that contradicted police officers' claims that victims died in a shootout. For example, in 33 cases, forensic evidence was at odds with the official version of what took place - including 17 cases in which autopsy reports show that police shot their victims at point blank range. The 51 cases do not represent the totality of potential extrajudicial killings, but are indicative of a much broader problem, the report concluded.

The report also draws upon extensive interviews with more than 40 criminal justice officials, including top prosecutors who view extrajudicial executions by the police as a major problem in both states.

Official government statistics support the prosecutors' assessment that the problem is widespread:

The Rio and São Paulo police have killed more than 11,000 people since 2003;

The number of police killings in Rio state reached a record high of 1,330 in 2007 and in 2008, the number was third highest at 1,137;

The number of police killings in São Paulo state, while less than in Rio, is also comparatively high: over the past five years, for example, there were more police killings in São Paulo state (2,176) than in all of South Africa (1,623), a country with a much higher homicide rate than São Paulo.

The high number of police killings is all the more dramatic when viewed alongside the comparatively low numbers of non-fatal injuries of civilians by police and of police fatalities.

The São Paulo Shock Police Command killed 305 people from 2004 through 2008 yet left only 20 injured. In all of these alleged "shootouts," the police suffered one death;

In Rio, police in 10 military policing zones were responsible for 825 "resistance" killings in 2008 while suffering a total of 12 police fatalities;

Rio police arrested 23 people for every person they killed in 2008, and São Paulo police arrested 348 for every kill. By contrast, police in the United States arrested over 37,000 for every person they killed in alleged confrontations that year.

"Police officers are permitted to use lethal force as a last resort to protect themselves or others," Vivanco said. "But the notion that these police killings are committed in self-defense, or justified by high crime rates, does not hold up under scrutiny."

In addition to the many "resistance" killings each year by police on duty, officers kill hundreds more while off-duty, often when they are acting as members of militias in Rio and death squads in São Paulo.

Police officers responsible for unlawful killings in Rio and São Paulo are rarely brought to justice. The principal cause of this chronic failure to hold police to account for murder, the report found, is that the criminal justice systems in both states currently rely almost entirely on police investigators to resolve these cases.

Human Rights Watch found that police officers frequently take steps to cover up the true nature of "resistance" killings. And police investigators often fail to take necessary steps to determine what has taken place, helping to ensure that criminal responsibility cannot be established and that those responsible remain unaccountable.

"So long as they are left to police themselves these executions will continue unchecked, and legitimate efforts to curb violence in both states will suffer," Vivanco said.

The report provides recommendations to Rio and São Paulo authorities for curbing police violence and improving law enforcement. The central recommendation is the creation of specialized units within state prosecutors' offices to investigate "resistance" killings and ensure that officers responsible for extrajudicial executions are brought to justice.

The report also details measures that state and federal authorities should take to maximize the effectiveness of these special units. These include:

Requiring police officers to notify prosecutors of "resistance" killings immediately after they take place;

Establishing and strictly enforcing a crime scene protocol that deters police officers from engaging in false "rescues" and other cover-up techniques;